there is a term for boy otaku's who get nastily into f/f. fundashi

And there is a term for girl otaku's who get nastifly into f/f. fujoshi

the west is the one that really separated them, though there is some sepration in mainstream japan. It should be noted that both terms do actually mean rotten girl/boy too.

if that isn't enough for you, they are still otaku which is...well you really don't get much lower then that there.